Problem 3 (24 Points; 12 points each for (a)-(b)) Consider a material which has yielded according to the von Mises yield criterion with y = 40 ksi. The dilatational strain is 0.001, the Young's modulus is 20x10 psi, and Poisson's ratio is 0.3. If = 0.001 and &=0.004, determine a) the principal deviatoric stresses, and b) the principal stresses.